The present invention is directed to a promoter, designated MuA, with less than 80% homology to a promoter of known activity. The construction of this promoter provides a general method for the discovery of novel sequences with utility as promoters. The present invention is also directed to DNA molecules including said promoter, such as a DNA construct comprising the promoter operably linked to one or more genes or antisense DNA. The invention is further directed to transformed plant tissue including the DNA molecule and to transformed plants and seeds thereof. The promoter is useful for driving gene or antisense expression for the purpose of imparting agronomically useful traits such as, but not limited to, increase in yield, disease resistance, insect resistance, herbicide tolerance, drought tolerance and salt tolerance in plants.
The publications and other materials used herein to illuminate the background of the invention, and in particular, cases to provide additional details respecting the practice, are incorporated by reference, and for convenience are referenced in the following text by author and date and are listed alphabetically by author in the appended bibliography.
The selection of a promoter in the genetic engineering of a heterologous gene is often a critical factor in obtaining expression of the desired gene. Promoters are typically found at the 5' end of a gene which is either directly or indirectly recognized and bound by a DNA-dependent RNA polymerase during the initiation of transcription of the gene. Consequently promoters play a major role in regulating gene expression. There are three general classes of promoters used in the genetic engineering of plants: 1) tissue specific promoters, 2) inducible promoters, and 3) constitutive promoters. Tissue specific or organ specific promoters drive gene expression in a certain tissue such as in the kernel, root, leaf, or tapetum of the plant. Chemicals or environmental stimuli such as heat, cold, wounding, and etc., induce inducible promoters. Although tissue specific and inducible promoters are required for certain applications, constitutive promoters are the most widely used promoters in the industry. Constitutive promoters are capable of driving a relatively high level of gene expression in most of the tissues of a plant. Constitutive promoters are particularly useful for producing herbicide tolerant plants. The most widely used constitutive promoter in the genetic engineering of plants is the CaMV 35S promoter; other constitutive promoters include the maize polyubiquitin promoter and the rice actin promoter. In general, those familiar with the art agree that constitutive promoters that drive a high level of heterologous gene expression in most of the tissues of a plant are few in number and are of considerable value in the field of genetic engineering of crop plants.
Thus, it is desired to develop additional constitutive promoters for use in plant transformation.